Go to the ChatGPT search extension page, then click the blue 'Add to Chrome' button and confirm the installation once prompted. That's all there is to do. Now when you start typing in the address bar you'll be searching with ChatGPT, not Google.

OpenAI unveiled SearchGPT inside ChatGPT last week and I’ve made the switch completely from Google in a large part because it removes all the clutter of a modern Google result page.

OpenAI's newly launched ChatGPT Search tool is almost ready to compete with Google Search (and there's already a Chrome extension).